Cam grinding machine



June 14, 1955 c. J. GREEN CAM GRINDING MACHINE IN VEN TOR. ELA/@Ence J GREEN A 'r 'roe/VFY I June 14, 1955 c. J. GREEN QAM GRINDING MACHINE Filed Feb. 19. 1953 6 Sheets-Sheei'I 2 June 14, 1955 c.. J. GREEN 2,710,495

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A TTOR Nsr United States Patent iiice 2,710,495 Patented June 14, 1955 CAM GRINDING MACHINE Clarence J. Green, Worcester, Mass., assignor to Norton Elompany, Worcester, Mass., a corporation of Massausetts Application February 19, 1953, Serial No. 337,703

9 Claims. (Cl. 51-101) The invention relates to grinding machines, and more particularly to an automatic cam grinding machine simultaneously to grind a plurality of cam shafts.

One object or" the invention is to provide a simple and thoroughly practical automatic cam grinding machine. Another object is to provide a multiple station cam grinding machine whereby the cams on a plurality of cam ,shafts are simultaneously ground. Another object is to provide a cam grinding machine having a rock bar arranged simultaneously to support a plurality of axially aligned rotatable cam shafts for a grinding operation. Another object is to provide a rock bar with a plurality of axially aligned rotatable cam shaft supports and a single set of master cams and a follower to control oscillation of the rock bar simultaneously to grind corresponding cams on a plurality of camshafts. Another object is to provide a wheel slide swivelling mechanism whereby a plurality of wheel slides may be swiveled simultaneously to position the grinding wheels supported thereby for taper cam grinding. Another object is to provide mechanismwhereby a plurality of grinding Wheels may be trued simultaneously and the reciprocation of each of the wheel spindles stopped automatically during the truing operation. Other objects will be in part obvious or in part pointed out hereinafter.

In the accompanying drawings, in which is shown one of various possible embodiments of the mechanical features of this invention:

Fig. 1 is a front elevation of the improved camhgrinding machine;

Fig. 2 is a plan view of the cam grinding machine; Fig. 3 is a right hand end elevation, on an enlarged scale, having parts broken away and shown in section to v clarify the construction;

Fig. 4 is a cross sectional view, on an enlarged scale, taken approximately on the line 4 4 of Fig. 2, showing the rock bar and mechanisms associated therewith;

Fig. 5 is a vertical longitudinal sectional view, on an enlarged scale, taken approximately on the line 5-5 ot' scale, of the hand wheel for actuating the grinding wheel feeding mechanism; l

Fig. l2 is a hydraulic diagram `of the control mechanisms of the machine; and

Fig. 13 is an electric wiring diagram of the electric control system of the machine.

A cam grinding machine has been illustrated in the drawings comprising a base which supports a longitudinally movable work table 11. The work table 11 is arranged to slide longitudinally relative to the base 10 on a flat-way 12 and a V-way 13 formed on the upper surface of the base 10.

A manually operable table traversing mechanism is provided comprising a hand traverse wheel 14 (Fig. 3) which is mounted on the left hand end of a rotatable shaft 15. The shaft 15 is provided with a gear 16 meshing with a gear 17 on a rotatable shaft 1S. The shaft 18 is provided with a gear 19 which meshes with a rack bar 20 xedly mounted on the under side of the table 11. It will be readily apparent from the foregoing disclosure that a rotary motion of the hand wheel 14 will be imparted through the mechanism above described to cause a longitudinal traversing movement of the table 11. The direction of rotation of the end wheel 14 serves to determine the direction of movement of the table 11.

The table 11 serves as a support for a rock bar 25 which is journalled in bearings 26, 27 and 28 formed in a bearing bracket 29, a housing 30, and the bearing bracket 31 respectively. For convenience of assembly the rock bar is preferably formed in three parts, namely, 25a, 25h and 25C which are keyed together so as to form an integrally arranged rock bar the axis of which is parallel to the axis of the grinding wheel to be hereinafter described.

The rock bar 25 is provided with a headstock 35 having a headstock center 36. A footstock 37 is also adjustably mounted on the rock bar 25 and is provided with a footstock center 38. The headstock center 36 and the headstock center 38 serve as supports for a cam shaft 39 to be ground. The footstock 37 is arranged so that it may be adjusted longitudinally relative to the rock bar to facilitate positioning the same for different lengths of cam shaft to be ground. The headstock is provided with a headstock spindle 40 which supports the center 36. The spindle 40 is journalled ina bearing 41. A rotatable drive shaft 42 (Fig. 5) is journalled in a bearing 43 carried by the bracket 29 and a spaced bearing 44 formed within vthe housing 30. The drive shaft 42 is provided with a 53 serves as a support for a cam shaft 54 to be ground.

The axis of the headstock center 36 and footstock center 38 are in axial alignment with the headstock center 51 an the footstock center 53.

The headstock is provided with a headstock or master cam spindle 55 which is supported in spaced hearings 56 and 57.

The master cam spindle 5S is provided with a sprocket 58 which is connected by a cog belt 59 mounted on the drive'shaft 42. An electric motor 61 is mounted on the table 11 and is provided with a multiple V-groove pulley 62 which is connected by multiple V-belts 63 with a multiple V-groove pulley 64 mounted on the left hand end of the drive shaft 42. It will be readily apparent that when the motor 61 is energized, a synchronous rotary motion will be imparted to the headstock spindle 40 and the master cam spindle 55.

The footstocks 37 and 52 are each provided with-a transverse adjustment comprising a dove-tailed slide-way 65 and an adjusting screw 66 by means of which the footstock may be adjusted transversely relative to the rock bar 25 to facilitate aligning the axes of the cam shafts 39 and 54 to be ground.

The master cam spindle 55 supports a plurality of master cams 67, only two of which have been illustrated in Figs. and 6. There is a master cam 67 for each cam to be ground on the cam shafts 39 and 54. A follower roller 68 is slidably keyed on a rotatable shaft 69 which is journalled in spaced bearings 70 and 71 carried by the housing 30.

A uid pressure mechanism, comprising a cylinder 75 xedly mounted within the housing 30 and containing a Vslidably mounted piston 76, is provided for rocking the rock bar 25 to and from an operative position. lt is desirable to rock the rock bar 25 to an inoperative position so as to separate the master cams 67 from the center roller 68 before the table 11 is indexed longitudinally. The piston 76 is connected to one end of a piston rod 77. A U-shaped frame 78 is clamped in a fixed position on the piston rods 77 by means of nuts 79. An upwardly extending arm Si) is iixedly mounted on the rock bar 25. The upper end of the arm 80 is provided with a pair of horizontally extending arms 81 and 82. A pair of tension spring 83 and 84 are connected at one end to the opposite ends of the U-shaped frame 78. The other ends of the springs 83 and 84 are connected by screws S5 and 86 respectively to the arms 81 and 82. By adjusting the screws 85 and 86, the tension of the springs 83 and 84 may be varied as desired. The arms 81 and 82 of the arm 80 are provided with rollers S7 and 8S respectively which are arranged to be engaged by the U-shaped frame 7S when the piston is moved toward the right (Fig. 4). When uid under pressure is admitted through a port 89 into a cylinder chamber 90 to move the piston 76 toward the right, the U-shapcd frame 78 will move into engagement with the rollers 87 and 88 after which continued movement of the piston 76 toward the right will swing the arm S0 in a clockwise direction to impart a clockwise movement to the rock bar 25 thereby separating the master cam 67 from the follower roller 63 during this movement of the piston 76. Fluid is exhausted from a cylinder chamber 91 through a port 92. The screws 85 and 86 are preferably adjusted so that when the piston 76 is at its extreme left hand end position, the tension of the springs 83 and 84 will be suftcientto maintain the master cam 67 in operation with the periphery o'f the follower roller 68 during rotation of the master cam spindle 55 so as to impart a controlled rocking movement to the rock bar 25 during a cam grinding operation.

As the piston 76 moves toward the right, to shift the rock bar 25 to an inoperative position, the U-shaped frame 78 moves toward the right and due to the clearance between the frame 78 and the rollers 87 and 88 relieves the tension of the springs 33 and 84. During movement of the piston 76 and frame 78 toward the right, the frame 78 engages the rollers 87 and 88 and rocks the arm 80 and rock bar 25 'to an inoperative position. By utilizing this construction, the extending and contracting of the springs 83 and 84 is reduced to a minimum. During movement of the piston 76 toward the left (Fig. 4), the master cam 67 engages the follower roller 68 after which the continued movement of the frame 78 toward the left separates the frame 78 from the rollers 87 and 88 and increases the tension on the springs 83 and 84 respectively to the desired operating tension.

A suitable indexing mechanism is provided which is actuated by and in timed relation with the indexing movement of the work table for indexing the master cam roller 68 longitudinally to position it in relationship with the master cam corresponding with the cam to be ground. This mechanism may be substantially the same as that shown in U. S. Patent No. 1,783,755 to C. G. Trefethen et al. dated December 2, 1930, to which reference may be had for details of disclosure not Contained herein. A bracket 99 fastened to the base 10 (Figs. 3 and 4) serves as a support for a dog bar 100 having a plurality of adjustable dogs 101 mounted thereon.

The dogs 101 are arranged in the path of movement of a star wheel 102 carried at the lower end of a shaft 103. The upper end of the shaft 103 is provided with a gear 104 which meshes with a gear 195 carried by a shaft 106. The shaft 106 also supports a gear 107 which meshes with a longitudinally slidable rack bar 108 supported within the housing 3 A yoked member 109 is fastened to the rack bar 108 and engages the side faces of the follower roller 68. It will be readily apparent from the foregoing disclosure that when the table 11 is moved longitudinally, the star wheel 102 engaging adjustable dogs 101 will impart an indexing movement through the gearing above described to index the master cam roller longitudinally to position it opposite the master cam 67 corresponding to the cam on the cam shafts 39 and 54 to be ground.

The base 10 serves as a support for a transversely movable wheel slide 110. The wheel slide 110 is supported on spaced ways, such as a at way 111 and a V-way 112. The wheel slide 110 supports a wheel spindle 113 in bearings (not shown). A grinding wheel 114 is mounted on the right hand end of the wheel spindle 113 (Figs. 1 and 2).

A suitable driving mechanism is provided for the wheel spindle 113 comprising a motor 115 adjustably supported on the upper surface of the wheel slide 110. The motor is provided with a motor shaft supporting a multiple V-.groove pulley 117. The pulley 117 is connected by multiple V-belts 118 with a multiple V-groove pulley 119 mounted on the left hand end of the wheel spindle 113. The electric motor is preferably supported on a platen which is adjustably mounted on the wheel slide. An adjusting screw 121 is provided to facilitate a transverse adjustment of the platen 120 relative to the wheel slide 110 to facilitate adjusting the motor 115 to tension the driving belts 118 as desired. The wheel slide 115 is positioned on the base 10 for bringing the grinding wheel 114 successively to grind the cams on the cam shaft 54.

A second wheel slide 110er is also supported on the base 10 on a dat way 111a and a V-way 112:1. The wheel slide 110:1 supports a rotatable wheel spindle 113a in suitable bearings (not shown) within the wheel slide 110. A grinding wheel 114:1 is mounted on the right hand end of the wheel spindle 113:2. The wheel slide 110:1 and the grinding wheel 114:1 are positioned on the base 10 so that the grinding wheel 114:1 will grind a corresponding cam on the cam shaft 39.

A suitable driving mechanism is provided comprising a motor 115:1 supported on the upper surface of the wheel slide 110:1. The motor 115:1 is provided with a motor shaft 116:1 carrying a multiple V-groove pulley 1170. The pulley 117:1 is connected by multiple V-belts 118:1 with a multiple V-groove pulley 119:: on the left hand end of the wheel spindle 1131:. The motor 115:1 is supported on a motor platen 120:1 which is adjustably supported on the wheel slide 110:1. An adjusting screw 121:1 is provided to facilitate a transverse adjustment of the motor platen 120a and the motor 115:1 to facilitate proper tensioning of the driving belts 118:1.

A suitable feeding mechanism is provided for feeding the grinding wheel slides 110 and 110:1 transversely successively to grind corresponding cams on the cam shafts 54 and 39 respectively. These feeding mechanisms are identical in construction, consequently only the feeding mechanism for the wheel slide 110 has been illustrated and will be described in detail. This mechanism may comprise a rotatable feed screw which is journalled in anti-friction bearings 126 and 127. The bearings 126 and 127 are fixedly supported on a wheel slide base 128. A nut 129 surrounds the feed screw 125 and is supported in spaced anti-friction bearings 130 and 131 carried within a housing 132. The housing 132 is xedly mounted on the underside of the wheel slide 110 (Fig. 3).

A manually operable mechanism is provided for iinparting a rotary motion to the feed screw 125. This mechanism may comprise a feed wheel 133 mounted on the left hand end of a rotatable shaft 134 which is supported within a housing 135 mounted on the upper portion of the wheel slide 110. The shaft 134 carries a bevel gear 136 which meshes with a bevel gear 137 mounted on the upper end of a vertically arranged rotatable shaft 138. The shaft 138 is connected by acoupling 139 with the upper end of a vertically arranged rotatable shaft 140. The lower end of the shaft 140 is provided with a bevel gear 141 which meshes with a bevel gear 142 slidably keyed on a horizontally arranged shaft 143. The shaft 143 is connected by a clutch with the feed screw 125. The shaft 143 supports a clutch member 144 having an internal gear formed thereon which is arranged to mesh with an external gear 145. The gear 145 is mounted on a rotatable sleeve 146 which is rotatably supported on a shaft 143. The shaft 143 is provided with a gear 148 which meshes with a gear 149 slidably keyed onto the feed screw 125. 1t will be readily apparent that a rotary motion of the hand wheel 133 will be mounted through the mechanism above described to rotate the feed screw 125 to impart a transverse feeding movement to the grinding wheel 114. The gear 149 is preferably connected to the housing 132 so that the gear 149 will be moved longitudinally relative to the feed screw 125 when the wheel slide 110 is fed transversely in either direction. The direction of rotation of the feed wheel 133 serves to determine the direction of movement of the slide 110 relative to the base 10.

It is desirable to provide a power operated mechanism for feeding the grinding wheel slide 110. This mechanism may comprise a liuid pressure cylinder 150 which is supported on the upper portion of the wheel slide 110 (Figs. 2, 3, and 12). The cylinder 150 contains a slidably mounted piston 151 having a rack 152 formed integrally therewith. The rack 152 meshes with a gear 153 which is Xedly mounted on the sleeve 146. It will be readily apparent that an endwise movement of the piston 151 will be transmitted through the rack 152, the gear 153 to rotate the gear 143, the gear 149 to impart a rotary motion to the feed screw 125.

When fluid under pressure is passed through a pipe 154 (Fig. l2) into a cylinder chamber 155, the piston 151 will be moved toward the right to impart a clockwise rotation to the gear 153 (Fig. l2) so as to impart a rotary motion to the feed screw 125 to cause an infeeding movement of the grinding wheel 114. During this movement fluid within a cylinder chamber 156 is exhausted through a pipe 157. Similarly when uid under pressure is passed through the pipe 157 into the cylinder chamber 156, the piston 151 will be moved toward the left (Fig. 12) to impart a counter-clockwise rotation to the gear 153 thereby rotating the feed screw 125 so as to cause a rearward movement of the wheel slide 110 and the grinding wheel 114.

A positive stop mechanism is provided to positively limit the infeeding movement of the wheel slide 110 when actuated either manually by rotation of the hand wheel 113 or by movement of the piston 151. This mechanism comprises a stop pawl 122 which is pivotally supported by a stud 123. The stop pawl 122 is arranged in the path of an adjustably mounted abutment 124 carried by the feed wheel 133.

An identical feeding mechanism is provided for the wheel slide 110:1 comprising a manually operable feed wheel 133:1 and a stop pawl 122:1. The details of the nut and screw feed are identical with those just described in connection with the feed mechanism for the slide 110, consequently they will not be illustrated or described in connection with the feed mechanism for the wheel slide 110:1. A fluid pressure cylinder 150:1 is provided for actuating the feed screw by power. The cylinder 150:1 contains a slidably mounted piston 151:1 having a rack 152:1 formed integrally therewith. The rack 152a meshes with a gear 153:: which is operatively connected to impart a rotary motion to the feed screw (not shown). When uid under pressure is passed through a pipe 154 into a cylinder chamber 155:1, the piston 151:1 will be moved toward the right so as to impart a clockwise movement to the gear 153:1 thereby imparting a rotary motion to the feed screw (not shown) so as to cause a receding movement of the wheel slide a. Similarly when fluid under pressure is passed through the pipe 157 into the cylinder chamber 156:1, the piston 151:1 will be moved toward the left so as to impart a counterclockwise motion to the gear 153:1 thereby causing a transverse movement of the wheel slide 110:1 to an inoperative position.

As illustrated in Fig. l2, the power operated feeding mechanisms are arranged so that both of the wheel slides 110 and 110:1 are simultaneously moved toward or from the cam on the cam shafts 54 and 39 to be ground. When fluid under pressure is passed through the pipe 154 into the cylinder chambers and 155:1, the pistons 151 and 151:1 will be simultaneously moved toward the right to cause a simultaneous infeeding movement to be imparted to the wheel slides 110 and 110e respectively. Similarly when fluid under pressure is passed through the pipe 157 into the cylinder chambers 156 and 156:1, the pistons 151 and 151:1 will be moved toward the left into the positions illustrated in Fig. l2 to cause a sirnnltaneous movement of the wheel slides 110 and 110:1 to a rearward or inoperative position.

A secondary feeding mechanism is provided for advancing both of the wheel slides for a truing operation so as to compensate for wheel wear and to feed the wheels by an amount to be trued therefrom. These mechanisms may comprise a feed compensator 220 mounted on the upper surface of the wheel slide 110 and a feed compensator 22%:1 mounted on the upper surface of the wheel slide 110:1 (Fig. 2). The feed compensators are arranged to impart a rotary motion to a vertical shaft 221 (Fig. 3) which is provided by its lower end with a worm 222 which meshes with a Worm gear 223 formed on the periphery of the feed nut 129. It will be readily apparent that a rotary motion of the shaft 121 will impart a rotary motion to thenut 129 to cause an advancing movement of the slide 110 so as to compensate for wheel wear and truing. The feed compensator 220 contains a fluid pressure cylinder 224 having a slidably mounted piston 225 contained therein. The piston 225 is connected to one end of a piston rod 226 which is connected through a rack and gear mechanism (not shown) to rotate the shaft 221. When uid under pressure is passed through a pipe 227 (Fig. 12), the piston-225 is moved toward the right. During this movement fluid within the other end of the cylinder 224 may exhaust through a pipe 228. This feed compensator is identical with that shown in the prior U. S. patent to C. J. Green and O. E. Hill No. 2,535,130 dated December 26, 1950, to which reference may be had for details of disclosure not contained herein.

Similarly the feed compensator 220:1 is provided with a cylinder 224:1 having a slidably mounted piston 225a which is connected to one end of a piston rod 226a. Fluid under pressure passing through either the pipe 227 or the pipe 228 simultaneously enters both of the cylinders 224 and 224:1 simultaneously to impart a compensating movement to the Wheel slides 110 and 110g.

It is desirable to provide a suitable mechanism for swivelling the Wheelk slides 116 and 110a in a horizontal plane to facilitate grinding tapered surfaces on the cams being ground. This is preferably accomplished in a manner substantially identical with that shown in my prior U. S. Patent No. 2,581,759 dated January 8, 1952, to which reference may be had for details of disclosure not contained herein. As illustrated in Fig. 2, the wheel slide 128 is arranged to pivot about a vertical stud 160. Similarly the wheel slide base 128:1 is arranged to pivot about a stud 160:1. The axis of the studs 160 and 160:1 are preferably located with their axes in` a mid-plane be- 'aviones provided with a yoke 166 which engages a rearwardly projecting stud 167 fixedly mounted on the wheel slide base 128. When iluid under pressure is passed through a pipe 168 into a cylinder chamber 169, the piston 164 will be moved toward the left to swing the wheel slide base 128 together with the wheel slide 110 and the grinding wheel 114 in a counter-clockwise direction. The swinging movement will continue until the wheel slide base 128 engages the Vstop screw 161. During this movement of the piston 164 fluid Within a cylinder chamber 170 may exhaust through a pipe 171. i the direction of flow of fluid under pressure is reversed and iluid under pressure is passed through the pipe 171 into the cylinder chamber 170, the piston 164 will be Vmoved toward the right to swing the Wheel slide base Similarly when.

128, the wheel slide 110 and the grinding wheel 114 in a clockwise direction until the wheel slide base 12.8 en- 4 gages the stop screw 162. By adjusting the position of the stop screws 161 and 162, the amount of swivel can be varied so that the periphery of the grinding wheel 114 will grind the desired and predetermined taper on the cam being ground.

In order to facilitate a grinding wheel truing operation, it is desirable to position the wheel slide base 128 together with the wheel slide 110 and the grinding wheel 114 in a central position so that the axis of the wheel spindle 113 is parallel to the path of movement of the work table 11 so that the operative face ofthe grinding wheel 114 may be trued by means of a truing tool 159 mounted on the table 11. In order to facilitate positioning the wheel slide base 128 in a central position, a hydraulically operated mechanism is provided comprising a cylinder 177 which contains a slidably mounted piston 178. The piston 178 is connected to one end of a piston rod 175 which serves as a stop stud which may be moved into or out of the path of a stop surface 176 formed on the wheel slide base 128. under pressure is passed through a pipe 179 into a cylinder chamber 180, the piston 178 will be moved into the position illustrated in Fig. 12. During this movement of the piston 178 fluid within a cylinder chamber 182 may exhaust through a pipe 181. When the ow of fluid under pressure is reversed and fluid is passed through the pipe 181 into the cylinder chamber 182, the piston 178 will be moved upwardly (Fig. l2) to withdraw the piston rod 175 out of the path of the stop surface 176, in which position the wheel slide base is"` free to swivel in either direction for a grinding operation.

A similar mechanism is provided for controlling the swivelling movement of the wheel slide base 128:1, the wheel slide 110a and the grinding wheel 114a. This mechanism may comprise a pair of adjustable stop screws 161a and 16241 supported on the base 10, a cylinder 163e mounted on the base 10 contains a slidably mounted piston 164:1 having a piston rod 165a which is connected by a yoked member 166a with a stud 167:1 projecting from the rear surface of the wheel slide base 128:1. When fluid under pressure is passed through a pipe 168:1 into a cylinder chamber 16941, the piston 16m-4ta will be moved toward the left so as to impart a counter-clockwise swivelling movement to the wheel slide base 128a, the wheel slide 110 and the grinding wheel 114:1. Similarly when fluid under pressure is passed through a pipc 171a into acylinder chamber 1700, the piston 164e will be moved toward the right so as to impart a clockwise A similar fluid operated stop mechanism is provided When fluid for locating the wheel slide base 128a in a central position for a truing operation. This mechanism comprises a cylinder 177a4which contains a slidably mounted piston 178a having a piston rod 175a which serves as a stop which may be moved into or out of the path of movement of a stop surface formed on the wheel slide base 12811. When fluid under pressure is passed through the pipe 179 it is conveyed simultaneously to the cylinder chambers 180 and 180a to move the stop pins 175 and 175:1 into an operative position as illustrated in Fig. l2. Similarly when tluid under pressure is passed through the pipe 181 it is simultaneously passed into the cylinder chambers 182 and 182a to withdraw the stop studs 175 and 175a.

A hydraulically operated table indexing mechanism is provided for entering the work table 11 longitudinally successively to position cams on the cam shafts 54 and 39 to be ground. This mechanism may comprise a cylinder which is ilxedly mounted to the underside of the table 11. The cylinder 190 contains a slidably mounted piston 191 which is connected to a double end piston rod 192 the opposite ends of which are xedly mounted to brackets 189 and 189:1 xedly mounted on the base 10. When fluid under pressure is passed through a'pipe 193 into a cylinder chamber 194, the cylinder 190 and the table 11 will be caused to move toward the right. During this movement, fluid within a cylinder chamber 195 may exhaust through a pipe 196. Similarly when fluid under pressure is passed through the pipe 196 into the cylinder chamber 195, the cylinder 190 together with the table 11 will be moved toward the left.

A shuttle type control valve 197 is provided for controlling the ilow of fluid to the cylinder 190. The valve 197 contains a slidably mounted valve member having a plurality of integral valve pistons 19S, 199, 200 and 201 forming a plurality of valve chambers 202, 203 and 204. When iluid under pressure is passed through a pipe 205 into an end chamber 206, the valve 197 is shifted into a left hand end position. During this movement tluid within the end chamber 207 may exhaust through a pipe 208. In the position of the valve 197 (Fig. l2) iluid under pressure passing through a pipe 209 enters the valve chamber 203 and passes through the pipe 196 into the cylinder chamber 195 to cause the cylinder 190 together with the table 11 to move toward the left. During this movement iluid within the cylinder chamber 194 may exhaust through the pipe 193 into the valve chamber 204 through a central passage 210 formed within the slidable member of the valve 197 into the valve chamber 202 and out through an exhaust pipe 211.

When iluid under pressure is passed through the pipe 208, the slidable valve member of the valve 197 is shifted toward the right so that fluid under pressure from the pipe 209 entering the valve chamber 203 passes through the pipe 193 into the cylinder chamber 194 to cause the cylinder 190 together with the table 11 to move toward the right.

A wheel spindle reciprocating mechanism is provided within each of the wheel slides 110 and 11011 for reciprocating the wheel spindles 113 and 113a respectively axially within their bearings during a grinding operation. This mechanism has not been illustrated in detail since it is an old and well known mechanism used in most grinding machines where a plunge-cut grinding operation is obtained. For details of disclosure not contained herein, reference may be had to the prior U. S. Patent No. 2,237,496 to G. T. Muskovin dated April 8, 194i. It is desirable to stop the wheel spindle reciprocation during a grinding wheel truing operation. To accomplish this result a cylinder 230 (Fig. l2) is provided. The cylinder 235B contains a slidably mounted piston 231 connected to one end of a piston rod 232. The piston rod 232 is operatively connected to stop oscillation of the wheel spindle when desired. A compression spring 233 contained within the cylinder 230 serves normally to lto the various mechanisms of the machine.

vsolenoid actuated pilot valve 263.

hold the piston 231 in va. left hand end position except when fluid under pressure is admitted through a pipe 234.into the cylinder chamber 235 to cause movement of the piston 231 toward the right to stop the reciprocation of the wheel spindle. A similar mechanism is provided for controlling the reciprocation of the Wheel spindle `113a. This mechanism may comprise a cylinder 230:1, a piston 231e, a piston rod 232a, a spring 23362 arranged in the same manner as previously described. When fiud under pressure is passed through the pipe 234 it passes simultaneously into the cylinder chambers 235 and 235a simultaneously to stop reciprocation of the wheel spindles 113 and 113a respectively.

A valve 240 serves when the solenoid S1 is deenergized to admit fiuid under pressure to a table index cylinder 245. The valve 249 is a piston type valve having a valve stem 241 which is normally held in a right hand end position by a compression spring 242. A fluid pressure pipe 243 conveys fluid to a valve chamber 244. When the solenoid S1 is energized, fluid entering the .valve chamber 244 passes through the pipe 234 to both of the cylinders 230 and 230i: to stop wheel spindle reciprocation.

The table index cylinder 245 is provided with a slidably mounted piston 246. A spring 247 normally serves to hold, the piston 246 in an upper motion position. In the position of valve 246 (Fig. 12) fluid under pressure entering the valve chamber 244 passes through a pipe 254 into a cylinder chamber 255 to cause a downward movement of the piston 246. The piston 246 is connected by a piston rod 2461:: with a plunger 252. A plunger 249 is slidably mounted with a central aperture lin the plunger 252. When the piston moves downwardly. the plunger 252 also moves downwardly and a cam face 253 on a plunger 249 actuates a plunger 251 to close a normally open limit switch LS6. The upper end of the plunger 249 is provided with an arrow point 250 which is arranged in the path of a plurality of table ndex dogs 243. The downward movement of the plunger 249 serves to open a normally closed limit switch LS3.

A uid pressure system is provided for supplying fluid under pressure to operate the various mechanisms of the vmachine comprising a motor driven uid pump 21S which draws fluid through a pipe 216 from a reservoir 217 and passes fluid under pressure through a pipe 218 A control valve 26) and a control valve 261 are 4provided to control the admission to and exhaust of fluid from the wheel feed cylinders 150 and 150e. The valve 260 is a shuttle type valve comprising a movable valve member 262 having a plurality of valve pistons formed integral therewith. The valve member 262 is arranged to be shifted by fluid under pressure controlled by a pilot valve 263 which is actuated by a solenoid S3 (Fig. 12). Fluid under pressure is passed through a pipe 264 from the pressure pipe 218 and also through a pipe 265 to the ln the position of the valve 263 (Fig. 11) fluid under pressure is admitted from the pilot valve to an end chamber in the right hand end of the control valve 260 to move the valve member 262 toward the left.

The valve 261 is similarly a shuttle type valve comprising a slidably mounted valve member 268 the movement of which is controlled by a pilot valve 269 actuated by a solenoid S8. Fluid under pressure is passed through a pipe 270 into a valve chamber formed at the right hand end of the valve 261 to shift the valve member 268 to its left hand end position.

In the position the valves 264) and 261 as illustrated in Fig. l2, fluid under pressure passing through the pipe 264, passes through a pipe 271, through a needle valve 272 into a right hand end chamber 273 formed in a backlash control valve 274. The backlash control valve 274 is a piston type valve comprising a pair of spaced valve pistons forming a valve chamber 275. During the 'initiall feeding movement of the grinding wheel, fiuid exhausting from the cylinder chambers y156 and .156:1 exhausts through a pipe v276. During this exhaust of fluid from the cylinder chambers 156 and 156g, fluid under pressure is admitted through a pipe 277 into a left hand end chamber 278 of thefbacklash valve 2,74 to shift the valve toward the right at a rate controlled by the needle valve 272. During this shifting movement of the backlash valve 274, the valve chamber 275 passing over a port formed in the pipe 276 allows a predetermined amount of uid to exhaust from the,pipe276 through the valve chamber 275 and out through an lexhaust pipe 279 into the reservoiry 217. The speed of movement of the valve 274 as controlled by the throttle valve 272 governs the amount of fluid permitted to'exhaust from the pipe 276. This exhaust of fluid is in addition to the regular controlled exhaust of uid from the cylinder chambers 156 and 156:1 and serves to provide an initial rapid movement of the feed pistons 151 and 151a to take up backlash in the feeding mechanism. A ball check valve 280 is provided in the pipe line 271 so that when fluid under pressure 'is passed through the pipe 271 it may pass substantially unrestricted into the end chamber 273 to cause a rapid return movement o the valve 274 into vits left hand end position.

Fluid under pressure passing through the pipe 271 may also pass through a throttle valve 281 which controls the normal rate of movement of the feed pistons 151 and 151@ in a manner to be hereinafter described. Fluid under pressure passing through the pipe 271 may also open a ball check valve 282 and pass substantially unrestricted through a pipe 283 into the valve 261. Fluid under pressure passing through the pipe 283 into the valve 261 passes through a central passage in the slidable valve member 26S and out through the pipe 276 into the cylinder chambers 156 and 156a to cause the pistons 151 and 15M to move toward the left. Movement of the pistons 151 and 151e toward the left serves through a gear mechanism above described to rotate the feed wheels 133 and 133a and the feed screws 125 and 125a to move the grinding wheels 114 and 114g and the supporting wheel slides and l10n rearwardly to an inoperative position. During movement ofthe pistons y151 and 15in toward the left fluid exhausting through the pipe 154 passes through the valve 261 and out through a pipe 284 into the valve 260, through a central passage formed in-the slidable valve member 262 and out through an exhaust pipe 285 into the reservoir 217. v

A pair of control valves 290 and 291 are provided to control the admission to and exhaust of uid from the shuttle valve 197 and to the table cylinder 190. The control valves l290 and 291 are substantially identical with the valves 260 and V261 and therefore have not been shown except diagrammatically in Fig. 12. The control valve 290 comprises a shuttle type slidably mounted valve member 292 and a pilot valve 293 which is actuated by a solenoid S2. Fluid under pressure from the pump 215 passing through the pipe 218 enters the pilot valve 293 and passes through a passage into the valve 296 to shift the valve into the left hand end position. mounted valve member 294 which is preferably a shuttle type valve the position of which is controlled by a pilot valve 295. The pilot valve 295 is actuated by a solenoid S7.

A small pipe 296, of approximately one-eighth inch in diameter connects the pipe 218 with the pipe 209 which serves when the valve 200 is positioned as shown vin Fig. 12 to pass a small quantity of fluid under pres- Similarly the valve 291 comprises a slidably` Vward the left.

uid under pressure to the valve chamber in the left hand end of the valve 290 to move the valve member 292 toward the right, tluid under pressure from the pipe 218 passes through the valve 290, through the pipe 211, through the shuttle valve 197 and through the pipe 193 into the cylinder chamber 194 to cause the table 11 to move toward the right,

Similarly when the shuttle valve 197 is moved toward the right into an extreme right hand end position, fluid under pressure passing through the pipe 211 passes through the pipe 196 into the cylinder chamber 195 to cause the cylinder 190 and the table 11 to move to- It will be readily apparent from the foregoing disclosure that when the solenoid S2 is energized, the valve 290 will be positioned to control the admission of fluid through the pipe 211 to the shuttle valve 197 and the table cylinder 190. When the solenoid S2 is deenergized, the valve 290 is positioned as shown in Fig. l2 to facilitate bypassing of iluid between opposite ends of the cylinder 190 to facilitate a manual traversing of the table 11. A reversing valve 300 actuated manually by means of a handle 351 serves normally to reverse the direction of flow of fluid to the opposite ends of the shuttle valve 197. The valve .300 may also be actuated automatically by and in timed relation with the longitudinal movement of the table 11 by a pair of reversing dogs 302 and 303.

Fluid exhausting through a pipe 305 during the normal table indexing movement may pass through a throttle valve 306 which serves to control the normal indexing speed of the table 11 and passes through a ball check valve 307, through a pipe 308 into the control valve 240 which is actuated by the solenoid S1. When solenoid S1 is energized and the valve member 241 is in its extreme left hand end position fluid passing from the pipe 308 may pass through the pipe 243 to a control valve 310. The control valve 310 is substantially identical with control valves 260 and 261 and comprises a slidably mounted valve member 311, and a pilot valve 312 which is actuated by a solenoid S4. When the solenoid S4 is deenergized as shown in Fig. l2 fluid under pressure from the pipe 21S passes through the valve 310, through the pipe 243 to the control valve 249. ln the position of the control valve 240 (Fig.

l2), fluid under pressure in the pipe 243 passes through' the pipe 254 into the cylinder chamber 25S to move the piston 246 downwardly against the compression of the spring 245 to withdraw the plungers 249 and 252 out ot' the path of the table dogs 248.

may pass through the pipe 234 into the cylinder chambers 235 and 235:: to move the pistons 231 and 231e so as to stop wheel spindle reciprocation.

When the solenoid S1 is energized, luid under pressure from the pipe 243' L.:

When the solenoid S4 is energized, iluid exhausts,

through a pipe 316 from the reversing valve 300 also f' passes into a chamber 317 formed at the lower end of a spring press valve 318. Pressure entering the valve chamber 317 raises a valve member 319 so that tluid within a pipe 320 may exhaust through a chamber in the valve 318 and pass out through a pipe 320, through a throttle valve 321, through a pipe 322, into the reservoir 217. The valve 318 is operative during the idle return stroke of the table 11 to facilitate a rapid return stroke so that fluid instead of having to pass through the throttle valve 306 may pass directly through the spring press valve 318 and the throttle valve 321 into the reservoir. The throttle valve 321 serves to regulate uid exhausting through 'the valve 31S so that the return of the idle stroke may be readily adjusted.

A pair of control valves 325 and 326 are provided for controlling the admission to and exhaust of fluid from the cylinders 163 and 163a respectively for controlling the swivelling movement of the wheel slide bases 12S and 12851. The control valve 32S comprises a slidably mounted valve member 327 and a pilot valve 328 which is actuated by a pair of solenoids S5 and S6. The con'- trol valve 326 comprises a slidably mounted valve member 329, and a pilot valve 330 which is actuated by means of a solenoid S9. In the position of the valves 325 and 326 (Fig. l2) fluid under pressure from the pipe 213 passes through the valve 325, through a pipe 331, through the control valve 326 and through the pipe 168 and 1680 into cylinder chambers 169 and 169a so as to cause the pistons 164 and 164a to move toward the left thereby imparting a counter-clockwise swivelling movenicht to the wheel slide bases 128 and 128:1, During this movement lluid within the cylinder chambers 170 and 170a may exhaust through the pipes 171 and 171a, through the valve 325 and through an exhaust pipe 332 into the reservoir 217. When the solenoid S5 is decnergized and the solenoid S6 is energized, the valve member 327 shifts to the left hand end position so that uid under pressure from the pipe 218 passes through the pipes 171 and 171a into the cylinder chambers 170 and 1700 to cause the pistons 164 and 164a to move toward the right so as to impart a clockwise swivelling movement to the wheel slide bases 128 and 12811.

The solenoid S9 is energized momentarily by an adjustable table dog 33S which momentarily closes a normally open limit switch LS10 when movement of the table 11 is started toward the right at the start of the grinding cycle, to shift the valve member 329 toward the right so that fluid under pressure passing through the pipe 331 from the valve 325 will pass through the pipes 181 and 181a into the cylinder chambers 182 and 182n respectively so as to withdraw the stop plungers 175 and 175e to an inoperative position. The limit switch LS1@ opens immediately after the dog 33S passes over the actuating roller to deenergize the solenoid S9 so that the valve member 329 shifts toward the left into the position illustrated in Fig. l2 thereby passing iluid under pressure through the pipes 168 and 16851 to cause the pistons 164 and 164a to move toward the left thereby swivelling the wheel slide bases 128 and 128:1 in a counterclockwise direction into engagement with the stop screws 161 and 161a. This swivelling movement serves to position the grinding wheels 114 and 114a in position to grind a taper on the first cam on the cam shafts 54 and 39 which tapers toward the left.

When the table is indexed longitudinally toward the right to position the second cam on the shafts 54 and 39 opposite the grinding wheels 114 and 114:1 respectively, a table dog 336 closes a normally open limit switch LS12 to energize solenoid S6 so as to shift the valve member 327 toward the left thereby passing uid under pressure through the pipes 171 and 171a into the cylinder chambers 170 and 170e to move the pistons 164 and 164a respectively toward the right thereby swinging the wheel slide bases 128 and 128e in a clockwise direction into engagement with the stop screws 162 and 162a respectively. This swivelling movement of the wheel slide bases 128 and 128e serves to swivel the grinding wheel slides 110 and 1104 and the grinding wheels 114 and 114e to position the operative faces of the wheels for grinding an opposite taper on the second cam on the cam shaft.

Similarly when the table is next indexed toward the right to position the third cam on the shafts 54 and 39 in operative relation with the grinding wheels 114 and 11411, a table dog 337 closes a normally open limit switch L11 to energize the solenoid S5 thereby shifting the valve member 327 into the position illustrated in Fig. l2 so that fluid under pressure is passed through the pipe 331 to the valve 326, and through the pipes 168 and 168g to cause the pistons 164 and 164:1 to move toward the left thereby imparting a counter-clockwise swivelling movement to the wheel slide bases 128 and 128a. This movement serves to position the grinding wheels 114 and 114:1 to grind an opposite taper on the third cam on the cam shafts 54 and 39. As shown in Fig. 2, the machine is set up to grind alternate cams on the cam shafts 54 and 39 which taper in opposite directions.

A plurality of dogs corresponding with dogs 336 and 337 are provided for imparting a swivelling movement to the wheel slide bases 128 and 12811 each time the table 11 is indexed toward the right to position a cam for a grinding operation. This mechanism is identical with that shown in my prior U. S. Patent No. 2,581,759 dated January S, 1952, to which reference may be had for details of disclosure not contained herein. During the idle stroke of the table 11 toward the left, the dogs 336 and 337 ride idly over the limit switches LS12 and LS11 respectively.

When the table 11 moves into position for a grinding wheel truing operation, the solenoid S1 is energized so that iiuid under pressure from the pipe 243 will pass through the pipe 234 into cylinder chambers 235 and 235e: to stop the axial reciprocation of the wheel spindles 113 and 113g respectively. Fluid under pressure passing through the pipe 234 passes also through the pipe 3118 into the cylinder chambers 180 and 180:1 to move the stop plungers 175 and 175e! into operative positions as shown in Fig. l2. The wheel slide bases 123 and 12851 are positioned in clockwise positions for grinding the taper on the left cam shaft. After the stop plungers 175 and 17551 are moved to an operative position, fluid is passed through the pipe 168 into cylinder chambers 169 and 169g to swivel the wheel slide bases 128 and 128g in a counterclockwise direction. The clockwise swivelling movement continues until the stop surfaces 176 and 176a move into engagement with the stop plungers 175 and 1756.' respectively to position the grinding wheel spindle into a position parallel with the table 11 so that a truing operation may he obtained. The rock bar 25 is provided with a pair of adjustably mounted diamonds or truing tools 195 and 19551 which are positioned so that the traversing movement of the table 11 will pass the truing tools 195 and 195e across the periphery of the grinding wheels 114 and 114g to true cylindrical surfaces thereon. This ytruing arrangement is likewise identical with that shown in my prior patent above referred to.

As previously mentioned the table 11 also is provided with a plurality of table index dogs 248 which serve precisely to position the table in successive grinding positions with successive cams positioned opposite the grinding wheels 114 and 1145i. This table indexing mechanism is identical with that disclosed in the prior U. S. Patent to C. J. Green and O. E. Hill No. 2,535,130 dated December 26, 195() to which reference may be had for details of disclosure not contained herein.

A cycle control lever 348 is pivotally mounted on the stud 349 on the front of the machine base. The cycle control lever 348 is arranged when rocked in a counterclockwise direction (Fig. 12) to close a normally open cycle start switch 354. When the lever 348 is rocked in a clockwise direction, a normally closed cycle stop switch 355 is opened.

As shown in Fig. 13 a normally open start switch 350 is provided for starting the grinding wheel driving motors 115 and 11521. A normally closed stop switch 351 is provided for stopping the wheel driving motors 115 and 115@ when desired. A normally open start switch 352 is provided for starting a motor 347 for driving the fluid pump 215. A normally closed stop switch 353 is provided to facilitate stopping they motor 347 when desired.

A normally open start switch 356 is provided for starting the work driving motor 61. A normally closed stop switch 357 is provided for stopping the motor 61 when desired. A stop control mechanism is provided for stopping the rotation of the work piece in a predetermined position which includes a cam 358 which is arranged to open a limit switch LS2 to stop the motor 61 with the work piece in a predetermined position. A jog switch 359 is provided to facilitate jogging the motor 61 in setting up the machine.

A main controllever 365 is mounted on the upper end of a vertically arranged shaft 366. The lower end of the shaft 366 is provided with an actuating arm 367 which is arranged to engage an actuating plunger for actuating a limit switch LS7. A compression spring j368 serves normally to hold the limit switch LS7 open. vA vertically arranged plunger 369 having an arrow-pointed upper end carries a laterally projecting arm 370 at its lower end. The arm 370 is arranged to actuate a pair of limit switches LS1 and LS9 when the plunger369 is moved in a vertical direction. A compression spring 371 serves normally to hold the plunger 369 in an upper-most position. As the table 11 is moved longitudinally, a dog 372 on the table 11 engages the arrow point on the plunger 369 to depress the plunger 369 so as to ,actuate both the limit switch LS1 and the limit switch LS9. A rotary motion of the main control lever 36S yserves to move a projecting stud 372 to actuate and open the normally closed limit switch LS7 in a manner to behereinafter described. This mechanism is substantially the same as that shown in the prior U. S. Patent No. 2,535,130 dated December 26, 1950, to which reference may be ha for details of disclosure not contained herein.

Operation 3G13. r111e start switch 350 is then actuated to lstart the grinding wheel driving motors 115 and 115'a. The start switch 352 is then actuated to start both the hydraulic pump motor 347 and lthe'coolant pump motor 346. The cycle control lever 348 is then rocked in a counterclockwise direction to close the cycle start switch 354 so as lto energize relay -switchlCRl and to render the cycle control mechanism operative. f V

A selector switch 380 is provided for rendering the electric timer 376 operative or inoperative. When the selector switch 380 is positioned as shown in Fig. 13, the electric counter 376 is operative to control the grinding cycle. As shown in Fig. 12 the parts have been illustrated when the machine is idle and the fluid pressure pump 215 is stopped. Similarly the parts shown in the electric diagram (Fig. 13) are shown with the power turned olf.

When it is desired to start a grinding cycle, the Vmain control lever 365 is raised against thecompression of the spring 368 to raise the stud 365i: out of the path of the cam on the table stop dog 373 after which the lever 365 H is moved toward the right to close the limit switch LS7 so as to energize the solenoid S2. '-Energizing the solenoid S2 serves to shift the valve member 292 into a right hand end position so that fluid under pressurel is passed through the pipe 211, through the valve 197, through the pipe 193 into the cylinder chamber 194 to start the table 11 moving toward the right. As the table 11 moves toward-the right, a table dog 373 moves o the plunger 369 thereby releasing the compression of the spring 371 so that the plunger 369 moves upwardly to actuate the limit switches LS1 and LS9. The'normally closed contacts of the limit switch LS9 open to deenergize the solenoid S1. The normally open contacts of the limit switch LS9 close and energize the relay switch CR3. Energizing relay CR3 serves to energize the solenoid S4 to exhaust fluid from the cylinder chamber 255 through the valve 240 thus allowing the plunger 252 to move upwardly into the path of the next table dog 248.

Before the rst dog 248 engages the arrow point 250 of the plunger 249, the dog 335 actuates the limit switch LS1() momentarily to energize the solenoid S9 towithdraw the plungers 175 and 175a to inoperative positions. As soon as the solenoid S9 deenergizes uid under pressure is passed from the valve 326 into the cylinder chambers 169 and 169a to swivel the wheel slide bases 128 and 128e in a counter-clockwise direction to position the grinding wheels 114 and 114a in a position for grinding the desired taper on the rst cams on the cam shafts 54 and 39 respectively.

The table 11 continues its movement toward the right until the dog 248 engages the arrow point 250 and causes a downward movement of the plunger 249 to open the limit switch LS3 and to close the limit switch LSG. The closing of the limit switch LS6 serves also to energize the solenoid S7 to shift the control valve 291 so that the fluid exhausting from the table cylinder 190 will pass through the throttle valve 306 to slow down the longitudinal movement of the table. The table 11 continues moving at a slow down-rate of speed until the index dog 24S moves into engagement with the plunger 252 to stop the table in an indexed position. The closing of the limit switch LS6 also serves to energize the solenoid S3 to pass fluid under pressure from the valve 260 to the rock bar cylinder 75 to cause the rock bar to move to an operative position and also to pass fluid under pressure through the control valve 261 to the feed cylinders 150 and 150a to start an infeeding movement of the grinding wheels 114 and 114g.

When lluid under pressure is admitted to the cylinder chamber 91 to move the rock bar 25 to an operative position for a grinding operation, movement of the arm 375 in a counter-clockwise direction (Fig. 12) serves to open the normally open limit switch L84 and to close the normally closed limit switch LSS. The closing of the limit switch L58 serves to render the electric counter 376 operative for a grinding cycle. The closing of the limit switch LSB serves also to energize a relay switch CR2 which closes a circuit to energize a relay switch MH automatically to start rotation of the work drive motor 61. When the selector switch 380 is in an off position, the work motor 61 may be manually controlled by actuation of the start switch 356.

During movement of the pistons 151 and 151:1 toward the right, fluid within the cylinder chambers 156 and 156:1 exhausts through the pipe 157, through the pipe 276, through the valve 261, through the pipe 283 and through the throttle valve 281 which may he regulated to control the rate of the infeeding movement of the grinding wheel. During the initial rapid feeding movement of the grinding wheels, thc backlash in the feed mechanism parts is taken up by allowing a predetermined amount of fluid to momentarily exhaust through the backlash valve 274. The amount of fluid exhausting through the backlash valve 274 may be controlled by the throttle valve 272 which serves to control the rate of movement of the valve 274.

During the cam grinding operation, the rock bar 25 is rocked by rotation of the master cams 67 in engagement with the follower roller 6%. During each oscillation of the rock bar 20, the limit switch LSS is actuated by an arm 375 to impart an impulse to an electric counter 376. When the counter 376 is rendered operative by the closing of limit switch L86, the contacts LC-l and RC1 are closed. After a predetermined numberof impulses, that is, actuation of the limit switch LSS by oscillation of the rock bar 25 during a grinding operation, the counter counts out and opens the contacts RC1 and LCI. At the start of the counting, the limit switch L53 is opened and the contacts LC1 and RC1 of the counter 376 are closed, so that the solenoid S4 is energized even though the limit switch L53 is opened by movement ot the table dog 248 causing a downward movement of the plunger 249. When the counter 376 counts out. the forward advancing of the grinding wheels is stopped and a rearward movement of the wheel `slides 11i*- and 110:1 is initiated. At countout of the counter 376, contacts LCI open and solenoid S4 is deenergized which serves to shift the valve 310 so as to pass uid under pressure through the pipe 243, through the valve 240, through the pipe 254 into cylindcr chamber 255 so as to cause a downward movement of the piston 246 thereby causing a downward movement of the plunger 252 out of the path of the table index dog 243 so that the table 11 is free to move toward the right. The solenoid S1 is deenergizerl during the entire grinding cycle and is energized only prior to and during a grinding wheel truing operation so as to stop axial reciprocation of the grinding wheels. During the downward movement of the plunger 252, the limit switch L86 is opened to deenergize the solenoid S3. The opening of the limit switch LSG serves to deenergize relay switch C114, thus opening a circuit to deenergize the solenoid S8. With the solenoid S8 deenergized, fluid under pressure from the reversng valve 366 passes through pipe 270 to shift the valve member 268 of the valve 261 into a left hand end position as shown in Fig. l2. With the valves 26) and 261 positioned as shown in Fig. l2, iiuid under pressure from the fluid pump 215 passes through the pipe 218 through the pipe 264, through the valve 263,. through the pipe 271, through ball check valve 2.82, through the valve 261, through the pipe 276 and the pipe 157 into the cylinder chambers 156 and 156.4 to cause the pistons 151 and 151a to move simultaneously toward the left to cause a rapid rearward movement of the grinding wheels 114 and 114g to inoperative positions. Fluid under pressure in the pipe 27 may also pass through the ball check valve 230 into the end chamber 273 of the backlash valve 274 to shift the valve toward the left into its initial position.

At the same time iuid under pressure is passed through the pipe 271 into the cylinder chamber 9i) to move the piston 76 toward the right (Fig. l2) to rock the bar 25 to an inoperative position so as to facilitate a longitudinal indexing movement of the table 11. The rocking of the bar 2S to an inoperative position serves to rock the arm 375 in a clockwise direction into the position illustrated in Fig. 12 thereby closing the normally open limit switch L54, opening the normally closed limit switch L58 and opening the normally closed limit switch LSS. Opening the limit switch LSS serves to deenergize the relay switch CRZ thereby breaking the circuit to deenergize the relay switch MH so as to break the circuit and thereby stop the work drive motor 61. Due to a holding circuit, the relay switch MH is deenergized, a circuit is maintained closed so that the motor 61 continues rotating the work until the cam 353 rotates through a partial rotation to open the normally closed limit switch L82 thereby breaking a circuit to stop the motor 61 with the camshaft in predetermined positions.

When the counter 376 counts out at the end of a grinding cycle, opening the contacts LC1 serves to deenergize the solenoid S4 thereby shifting the valve 31() into the position illustrated in Fig. 12 so that fluid under pressure is passed through the pipe 243, through the valve 260, through the pipe 254 into the cylinder chamber 255 to move the piston 246 downwardly thereby withdrawing the plunger 252 out of the path of the table index dog 24S. The closing of the limit switch L84 by movement of the rock bar 25 to an inoperative position serves to energize the solenoid S2 so that fluid under pressure is passed through the pipe 211, through the valve 197, through the pipe 193 into the cylinder chamber 194 to move the cylinder and the table 11 tov/ard the right to index the next cams to be ground into an operative position relative to the grinding wheels 114 and 11451 respectively. As the next table dog 243 moves toward the right, it engages the arrow point 250 and depresses the plunger 249 to slow down the movement of the table 11, in a manner above described, before the dog 248 engages the upper end of the plunger 252 to stop the table 11 in the next indexed position. The grinding cycle of the next cam is repeated in a manner above described in connection with the grinding of the irst cam on the cam shaft. This cycle of operation is repeated for each cam on the cam shaft to be ground. During each indexing movement of the table 11, the master cam follower roller 68 is indexed longitudinally into operative relation with the master cam 67 on the cam shaft 55.

After all of the cams have been ground as the table 11 is successively indexed toward the right, the table 11 moves a further distance toward the right beyond the last cam on the cam shafts being ground until the reversing dog 302 engages and actuates the reversing valve 39) to shift the valve into a reversing position so that the table 11 will move rapidly toward the left into an initial position.

During each table indexing movement toward the right, one of the dogs 336 or 337 actuates one of the limit switches LS12 or LS11' respective.y so as to cause a swivelling movement of the wheel slides 119 and 116m to grind successive cams tapering in the opposite direction. As shown in the drawing, when the last cams on the left hand ends of the cam shaft 54 and 39 are ground, the limit switch LS12 is closed so that solenoid S6 is energized and iuid under pressure passes through the valve 325 through the pipe 171 to move the pistons 164 and 16451 toward the right to swivel the wheel slide bases 128 and 123g in a clockwise direction.

On the return stroke of the table, that is, toward the left, the rapid speed continues until the stop dog 372 engages and actuates the plunger 369 (Fig. l2) which serves to actuate both the limit switches LS1 and LS9. At this time the solenoids S1 and S4 are both energized so that no fluid under pressure may pass through either the pipe 243 or the pipe 234. Downward movement of the plunger 369 opens the closed contacts of the limit switch LS1 to deenergize the solenoids S1 and S5. The closing of the open contacts of LS1 and LS9 serves to energize the relay switch CRS to energize the solenoid S4 thereby allowing uid to pass through the pipe 243, through the valve 246, through the pipe 254 to cause a downward movement of the piston 246 thereby withdrawing the plunger 252 out of the path of the truing dog 301. The downward movement-of the plunger 252 serves to open the limit switch LSG thereby deenergizing the solenoid S7 to shift the valve 291 into the position illustrated in Fig. 12 so that iluid exhausting from the cylinder chamber 194 passes through the valve 297, through the pipe 211, through the valve 290, through the pipe 209, through the valve 291 and through a pipe 396 and a throttle valve 391, through the throttle valve 306,

through the ball check valve 367 and through the exhaust pipe 30S into the reservoir 217. By regulation ofthe throttle valve 391 the movement of the table 11 may be slowed to a very slow truing speed for a grinding wheel truing operation.

At the same time the truing dog 386 engages the plunger 249, the table stop dog 372 engages and depresses the plunger 369 depressing the plunger 369 shiftsl the limit switches LS1 and LS9 into the positions illustrated in Figs. l2 and 13. The closing of the lower contacts of limit switches LS1 and LS9 serves to energize the solenoid S1 and S5. Energizing the solenoid S1 serves to pass fluid under pressure through the pipe 234 into the cylinder chambers 235 and 235a to stop the grinding wheel spindle reciprocation. Fluid under pressure passes simultaneously through the pipe 30S into the cylinder chambers 133 and 18th: to cause the stop plungers 175 and 17551 to move downwardly into the position illustrated in Fig. l2. Energizing of the solenoid S serves to pass fluid under pressure through the pipe 331, through the valve 326 and through the pipe 168 into cylinder chambers 169 and 169a to cause the pistons 164 and 164g to swivel the wheel slide bases 128 and 128g in a counterclockwise direction so that the stop surfaces 176 and 176a engage the stop plunger 175 and 175a respectively so as to position the grinding wheels in a truing position.

The table 11 continues its travel toward the left at a truing speed while the plungers 249 and 369 ride on the bottom surfaces of the dogs 400 and 372 respectively while the truing tools 159 and 159a pass across the peripheral faces of the grinding wheels 114 and 114:1 to true the same. At the time the reversing dog 362 shifts the reversing valve 300 at the right hand end of the table stroke, uid under pressure is passed into the wheel feed compensators 224 and 224e to impart a compensating feed to the wheel slides and 110m This movement advances the grinding wheels by a predetermined amount for the truing operation. The truing movement of the table 11 toward the left continues until reversing dog 303 engages and actuates the reversing valve 300 to shift the ow of uid to the table cylinder so as to start the table 11 moving in the reverse direction. At the same time fluid under pressure is passed through the pipe 227 to impart a second compensating feed to the grinding wheel slides 116 and 11ml before the truing tools 159 and 159a move into engagement with the grinding wheels 114 and 114a for a second pass of the truing tools across the peripheral faces of the wheels. This movement of the table 11 toward the right continues until the dog 373 engages the lug 365a and rotates the lever 365 in a clockwise direction so as to open the limit switch LS7 and thereby stops the table 11 in a loading position while the ground work pieces are removed and new pieces of work to be ground are inserted there instead. It will thus be seen that there has been provided by this invention apparatus in which the various objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. As many possible embodiments may be made of the above invention and as many changes might be made in the embodiment above set forth, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

Ir claim: l v l. In a camshaft grinding machine having a base, a plurality of spaced transversely movable wheel slidesthereon, a rotatable grinding wheel on each of said slides, a longitiidinally movable table on said base, a rock bar pivotal-l 1 ly mounted on said table, the pivotal axis of the rock bar being parallel to the axis of said grinding wheels, a plurality of spaced axially alignedheadstocks and footstocks on said rock barsimultaneously to support a plurality of camshafts to be ground, a rotatable spindle on each'of said headsto'cks, means including a single motor on said table operatively connected synchronously to rotate all of said headstock spindles, means including a single set of spaced master cams mountedhon one ofisaid spindles, and ayfollower single roller successively engageable therewith and rotatably supported on said table to impart a rocking movement to said rock bar simultaneously to grind corresponding cams on each of the camshafts to be ground.

2. In a camshaft grinding machine having a base, a pair of spaced transversely movable wheel slides thereon, a rotatable grinding wheel on each of said slides, a longitudinally movable table on said base, a rock bar pivotally mounted on said table, the pivotal axis of the rock bar being parallel to the axis of said grinding wheels, a pair of spaced axially aligned headstocks and footstocks on said rock bar simultaneously to support a pair of carnshafts each having a plurality of spaced cams to be ground in axial alignment with each other, a rotatable spindle on each of said headstocks, means including a single motor on said table operatively connected synchronously to rotate both of said headstock spindles, means including a single set of spaced master cams on one of said spindles, and a follower roller engageable therewith and rotatably supported on said table to impart a rocking movement to It? said rock bar simultaneously to grind 'corresponding cams on each of the camshafts to be ground.

3. In a camshaft grinding machine having a base, a pair of spaced transversely movable wheel slides thereon, arotatable grinding wheel'on each of said slides, a longitudinally movable table on said base, an independent feeding mechanism including an independent fluid motor for feeding each of said slides toward andfrom said table, Vmeans including a single control valve mechanism simultaneously to control said fluid motors so as to cause a simultaneous infeeding movement of both ofthe wheel slides, means inc'luding a iluid motor to index "said table longitudinally, a rock bar pivotally mounted o'n said table, a pair of spaced axially aligned headstocks and footstocks on 'said rock bar simultaneously to support a pair of camshafts to be ground, a 'rotatable spindle on each of said headstocks, means includinga single motoren said table synchronously to rotate both of said spindles, means'including asingle set of spaced master cams on one of said spindles, vandra master cam follower roller successively engageable therewith and rotatably supported on said table to impart a rocking movement to said rock bar simultaneously to grind corresponding cams on each of the camshafts to be ground.

4. In a camshaft grinding machine as claimed in claim 1, in combination with the parts 'and features therein specied of a vertical pivot for each of said wheel slides tofacilitate a swivelling movement of the slides in ahorizontal plane, an independent uid motor operatively connected to swivel each of said slides ineither direction, and a single control valve mechanism actuated by and in timed relation with the table movement simultaneously to control all of said sv/ivelling motors so as 'to simultaneously swivel each of the wheel slides in one direction to position the grinding wheels for grinding a predetermined taper in one direction on part of the corresponding cams on each of said camshafts and simultaneously to swivel said slides in the opposite direction simultaneously to grind a predetermined taper in the opposite direction on the remainder of the corresponding cams on each of said camshafts.

5. In a camshaft grinding machine, as claimed in 'claim 1, in combination with the partsand features therein specified of a vertical pivot foreach of the wheel slides tofailitate a swivellingmovernent of the slides ina horizontal plane, an independent Viluid motor operatively connected to swivel each of said slides in either direction, anda single control valve mechanism actuated by and in timed relation with the table movement simultaneously to control all of the huidV motors so Vas to alternatelyand simultaneously swivel said slides in the opposite directionsaftereach cam has been ground to facilitate grinding a predetermined taper in opposite directions on corresponding 'alternate cams on each of said camshafts to be ground.

6. In a camshaft grinding machine, Vas claim-ed in 'claim 1, in combination with the-parts and features therein speciiied of an independent wheel spindle reciprocating mechanism for each ofthe grinding wheel slides, means including an independent piston and cylinder to render each of said reciprocating mechanisms inoperative, and means including a 'single control valve mechanism simultaneously to control the admission to and exhaust of fluid from said cylinders so as to simultaneously stop reciprocation of both of the wheel spindles during a grinding wheel truing operation.

7. in a camshaft'grindingmachine, as claimed in claim 1',ir1 combination with the-parts andfeatures therein specitied in which the wheel feeding mechanism comprises a manually operable nut and screw mechanism, an independent wheel feed compensator for each of said feeding mechanism which are arranged to actuate said nut and screw mechanism to advance each of the grinding wheels prior to a truing operation, vand means including a single control valve mechanism to control the admission to and exhaust of uid from the feed compensators so as simultaneously to advance all of the wheel slides by a predetermined amount before each pass of the truing tool across the face of the grinding wheel.

8. In a camshaft grinding machine, as claimed in claim l, in combination with the parts and features therein specilied of `an independent locating plunger for locating each of the wheel slides in a central position for a grinding wheel truing operation, an independent piston and cylinder for actuating each of said plungers, and means inciuding a `single control valve mechanism to control the admission to and exhaust of fluid'from said cylinders automatically and simultaneously to move the plungers into an operative position before a truing operation.

9. In a camshaft grinding machine, as claimed in claim l, in combination with the parts and features therein specified of an independent piston and cylinder for swivelling each of the wheel slides in opposite directions precisely to position the grinding wheels for grinding opposite tapers on the cams beingground, means including an independent locating plunger for locating each of the wheel slides in a central position for a grinding wheel truing operation, an independent piston and cylinder for actuating each of said plungers, and means including a single control valve for simultaneously controlling the admission to and exhaust of "uid from the swivelling and plunger actuating cylinders.

'References Cited inthe file of this patent UNITED STATES PATENTS 1,254,253 Marchant Jan. 22, 1918 2,535,130 Green etal Dec. 26, 1950 A2,581,759 Green Jan. S, 1952 2,641,089 Fouquet June 9, 1953 

